diff --git a/wpiutil/src/main/java/edu/wpi/first/util/datalog/DataLog.java b/wpiutil/src/main/java/edu/wpi/first/util/datalog/DataLog.java
index 7fd8636cad..1003f80a51 100644
--- a/wpiutil/src/main/java/edu/wpi/first/util/datalog/DataLog.java
+++ b/wpiutil/src/main/java/edu/wpi/first/util/datalog/DataLog.java
@@ -4,6 +4,8 @@
 
 package edu.wpi.first.util.datalog;
 
+import java.nio.ByteBuffer;
+
 /**
  * A data log. The log file is created immediately upon construction with a temporary filename. The
  * file may be renamed at any time using the setFilename() function.
@@ -191,11 +193,49 @@ public final class DataLog implements AutoCloseable {
    * Appends a raw record to the log.
    *
    * @param entry Entry index, as returned by start()
-   * @param data Byte array to record
+   * @param data Byte array to record; will send entire array contents
    * @param timestamp Time stamp (0 to indicate now)
    */
   public void appendRaw(int entry, byte[] data, long timestamp) {
-    DataLogJNI.appendRaw(m_impl, entry, data, timestamp);
+    appendRaw(entry, data, 0, data.length, timestamp);
+  }
+
+  /**
+   * Appends a record to the log.
+   *
+   * @param entry Entry index, as returned by start()
+   * @param data Byte array to record
+   * @param start Start position of data (in byte array)
+   * @param len Length of data (must be less than or equal to data.length - start)
+   * @param timestamp Time stamp (0 to indicate now)
+   */
+  public void appendRaw(int entry, byte[] data, int start, int len, long timestamp) {
+    DataLogJNI.appendRaw(m_impl, entry, data, start, len, timestamp);
+  }
+
+  /**
+   * Appends a record to the log.
+   *
+   * @param entry Entry index, as returned by start()
+   * @param data Buffer to record; will send from data.position() to data.limit()
+   * @param timestamp Time stamp (0 to indicate now)
+   */
+  public void appendRaw(int entry, ByteBuffer data, long timestamp) {
+    int pos = data.position();
+    appendRaw(entry, data, pos, data.limit() - pos, timestamp);
+  }
+
+  /**
+   * Appends a record to the log.
+   *
+   * @param entry Entry index, as returned by start()
+   * @param data Buffer to record
+   * @param start Start position of data (in buffer)
+   * @param len Length of data (must be less than or equal to data.capacity() - start)
+   * @param timestamp Time stamp (0 to indicate now)
+   */
+  public void appendRaw(int entry, ByteBuffer data, int start, int len, long timestamp) {
+    DataLogJNI.appendRaw(m_impl, entry, data, start, len, timestamp);
   }
 
   @Override
diff --git a/wpiutil/src/main/java/edu/wpi/first/util/datalog/DataLogJNI.java b/wpiutil/src/main/java/edu/wpi/first/util/datalog/DataLogJNI.java
index 724b3d96fc..85c85251b1 100644
--- a/wpiutil/src/main/java/edu/wpi/first/util/datalog/DataLogJNI.java
+++ b/wpiutil/src/main/java/edu/wpi/first/util/datalog/DataLogJNI.java
@@ -5,6 +5,7 @@
 package edu.wpi.first.util.datalog;
 
 import edu.wpi.first.util.WPIUtilJNI;
+import java.nio.ByteBuffer;
 
 public class DataLogJNI extends WPIUtilJNI {
   static native long create(String dir, String filename, double period, String extraHeader);
@@ -25,7 +26,30 @@ public class DataLogJNI extends WPIUtilJNI {
 
   static native void close(long impl);
 
-  static native void appendRaw(long impl, int entry, byte[] data, long timestamp);
+  static native void appendRaw(
+      long impl, int entry, byte[] data, int start, int len, long timestamp);
+
+  static void appendRaw(long impl, int entry, ByteBuffer data, int start, int len, long timestamp) {
+    if (data.isDirect()) {
+      if (start < 0) {
+        throw new IndexOutOfBoundsException("start must be >= 0");
+      }
+      if (len < 0) {
+        throw new IndexOutOfBoundsException("len must be >= 0");
+      }
+      if ((start + len) > data.capacity()) {
+        throw new IndexOutOfBoundsException("start + len must be smaller than buffer capacity");
+      }
+      appendRawBuffer(impl, entry, data, start, len, timestamp);
+    } else if (data.hasArray()) {
+      appendRaw(impl, entry, data.array(), data.arrayOffset() + start, len, timestamp);
+    } else {
+      throw new UnsupportedOperationException("ByteBuffer must be direct or have a backing array");
+    }
+  }
+
+  private static native void appendRawBuffer(
+      long impl, int entry, ByteBuffer data, int start, int len, long timestamp);
 
   static native void appendBoolean(long impl, int entry, boolean value, long timestamp);
 
diff --git a/wpiutil/src/main/java/edu/wpi/first/util/datalog/RawLogEntry.java b/wpiutil/src/main/java/edu/wpi/first/util/datalog/RawLogEntry.java
index 160f734e55..972fc03cfa 100644
--- a/wpiutil/src/main/java/edu/wpi/first/util/datalog/RawLogEntry.java
+++ b/wpiutil/src/main/java/edu/wpi/first/util/datalog/RawLogEntry.java
@@ -4,6 +4,8 @@
 
 package edu.wpi.first.util.datalog;
 
+import java.nio.ByteBuffer;
+
 /** Log raw byte array values. */
 public class RawLogEntry extends DataLogEntry {
   public static final String kDataType = "raw";
@@ -35,7 +37,7 @@ public class RawLogEntry extends DataLogEntry {
   /**
    * Appends a record to the log.
    *
-   * @param value Value to record
+   * @param value Value to record; will send entire array contents
    * @param timestamp Time stamp (0 to indicate now)
    */
   public void append(byte[] value, long timestamp) {
@@ -45,9 +47,74 @@ public class RawLogEntry extends DataLogEntry {
   /**
    * Appends a record to the log.
    *
-   * @param value Value to record
+   * @param value Value to record; will send entire array contents
    */
   public void append(byte[] value) {
-    m_log.appendRaw(m_entry, value, 0);
+    append(value, 0);
+  }
+
+  /**
+   * Appends a record to the log.
+   *
+   * @param value Data to record
+   * @param start Start position of data (in byte array)
+   * @param len Length of data (must be less than or equal to value.length - offset)
+   * @param timestamp Time stamp (0 to indicate now)
+   */
+  public void append(byte[] value, int start, int len, long timestamp) {
+    m_log.appendRaw(m_entry, value, start, len, timestamp);
+  }
+
+  /**
+   * Appends a record to the log.
+   *
+   * @param value Data to record
+   * @param start Start position of data (in byte array)
+   * @param len Length of data (must be less than or equal to value.length - offset)
+   */
+  public void append(byte[] value, int start, int len) {
+    append(value, start, len, 0);
+  }
+
+  /**
+   * Appends a record to the log.
+   *
+   * @param value Data to record; will send from value.position() to value.capacity()
+   * @param timestamp Time stamp (0 to indicate now)
+   */
+  public void append(ByteBuffer value, long timestamp) {
+    m_log.appendRaw(m_entry, value, timestamp);
+  }
+
+  /**
+   * Appends a record to the log.
+   *
+   * @param value Data to record; will send from value.position() to value.capacity()
+   */
+  public void append(ByteBuffer value) {
+    append(value, 0);
+  }
+
+  /**
+   * Appends a record to the log.
+   *
+   * @param value Data to record
+   * @param start Start position of data (in value buffer)
+   * @param len Length of data (must be less than or equal to value.length - offset)
+   * @param timestamp Time stamp (0 to indicate now)
+   */
+  public void append(ByteBuffer value, int start, int len, long timestamp) {
+    m_log.appendRaw(m_entry, value, start, len, timestamp);
+  }
+
+  /**
+   * Appends a record to the log.
+   *
+   * @param value Data to record
+   * @param start Start position of data (in value buffer)
+   * @param len Length of data (must be less than or equal to value.length - offset)
+   */
+  public void append(ByteBuffer value, int start, int len) {
+    append(value, start, len, 0);
   }
 }
diff --git a/wpiutil/src/main/native/cpp/jni/DataLogJNI.cpp b/wpiutil/src/main/native/cpp/jni/DataLogJNI.cpp
index 997b90b158..faf910dc65 100644
--- a/wpiutil/src/main/native/cpp/jni/DataLogJNI.cpp
+++ b/wpiutil/src/main/native/cpp/jni/DataLogJNI.cpp
@@ -4,7 +4,9 @@
 
 #include <jni.h>
 
+#include "WPIUtilJNI.h"
 #include "edu_wpi_first_util_datalog_DataLogJNI.h"
+#include "fmt/format.h"
 #include "wpi/DataLog.h"
 #include "wpi/jni_util.h"
 
@@ -23,6 +25,18 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_create
   (JNIEnv* env, jclass, jstring dir, jstring filename, jdouble period,
    jstring extraHeader)
 {
+  if (!dir) {
+    wpi::ThrowNullPointerException(env, "dir is null");
+    return 0;
+  }
+  if (!filename) {
+    wpi::ThrowNullPointerException(env, "filename is null");
+    return 0;
+  }
+  if (!extraHeader) {
+    wpi::ThrowNullPointerException(env, "extraHeader is null");
+    return 0;
+  }
   return reinterpret_cast<jlong>(new DataLog{JStringRef{env, dir},
                                              JStringRef{env, filename}, period,
                                              JStringRef{env, extraHeader}});
@@ -38,6 +52,11 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_setFilename
   (JNIEnv* env, jclass, jlong impl, jstring filename)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
+    return;
+  }
+  if (!filename) {
+    wpi::ThrowNullPointerException(env, "filename is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->SetFilename(JStringRef{env, filename});
@@ -50,9 +69,10 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_setFilename
  */
 JNIEXPORT void JNICALL
 Java_edu_wpi_first_util_datalog_DataLogJNI_flush
-  (JNIEnv*, jclass, jlong impl)
+  (JNIEnv* env, jclass, jlong impl)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->Flush();
@@ -65,9 +85,10 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_flush
  */
 JNIEXPORT void JNICALL
 Java_edu_wpi_first_util_datalog_DataLogJNI_pause
-  (JNIEnv*, jclass, jlong impl)
+  (JNIEnv* env, jclass, jlong impl)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->Pause();
@@ -80,9 +101,10 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_pause
  */
 JNIEXPORT void JNICALL
 Java_edu_wpi_first_util_datalog_DataLogJNI_resume
-  (JNIEnv*, jclass, jlong impl)
+  (JNIEnv* env, jclass, jlong impl)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->Resume();
@@ -99,6 +121,7 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_start
    jstring metadata, jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
     return 0;
   }
   return reinterpret_cast<DataLog*>(impl)->Start(
@@ -113,9 +136,10 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_start
  */
 JNIEXPORT void JNICALL
 Java_edu_wpi_first_util_datalog_DataLogJNI_finish
-  (JNIEnv*, jclass, jlong impl, jint entry, jlong timestamp)
+  (JNIEnv* env, jclass, jlong impl, jint entry, jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->Finish(entry, timestamp);
@@ -132,6 +156,7 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_setMetadata
    jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->SetMetadata(
@@ -153,21 +178,73 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_close
 /*
  * Class:     edu_wpi_first_util_datalog_DataLogJNI
  * Method:    appendRaw
- * Signature: (JI[BJ)V
+ * Signature: (JI[BIIJ)V
  */
 JNIEXPORT void JNICALL
 Java_edu_wpi_first_util_datalog_DataLogJNI_appendRaw
-  (JNIEnv* env, jclass, jlong impl, jint entry, jbyteArray value,
-   jlong timestamp)
+  (JNIEnv* env, jclass, jlong impl, jint entry, jbyteArray value, jint start,
+   jint length, jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
+    return;
+  }
+  if (!value) {
+    wpi::ThrowNullPointerException(env, "value is null");
+    return;
+  }
+  if (start < 0) {
+    wpi::ThrowIndexOobException(env, "start must be >= 0");
+    return;
+  }
+  if (length < 0) {
+    wpi::ThrowIndexOobException(env, "length must be >= 0");
+    return;
+  }
+  CriticalJByteArrayRef cvalue{env, value};
+  if (static_cast<unsigned int>(start + length) > cvalue.size()) {
+    wpi::ThrowIndexOobException(
+        env, "start + len must be smaller than array length");
     return;
   }
-  JByteArrayRef cvalue{env, value};
   reinterpret_cast<DataLog*>(impl)->AppendRaw(
-      entry,
-      {reinterpret_cast<const uint8_t*>(cvalue.array().data()), cvalue.size()},
-      timestamp);
+      entry, cvalue.uarray().subspan(start, length), timestamp);
+}
+
+/*
+ * Class:     edu_wpi_first_util_datalog_DataLogJNI
+ * Method:    appendRawBuffer
+ * Signature: (JILjava/lang/Object;IIJ)V
+ */
+JNIEXPORT void JNICALL
+Java_edu_wpi_first_util_datalog_DataLogJNI_appendRawBuffer
+  (JNIEnv* env, jclass, jlong impl, jint entry, jobject value, jint start,
+   jint length, jlong timestamp)
+{
+  if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
+    return;
+  }
+  if (!value) {
+    wpi::ThrowNullPointerException(env, "value is null");
+    return;
+  }
+  if (start < 0) {
+    wpi::ThrowIndexOobException(env, "start must be >= 0");
+    return;
+  }
+  if (length < 0) {
+    wpi::ThrowIndexOobException(env, "length must be >= 0");
+    return;
+  }
+  JByteArrayRef cvalue{env, value, start + length};
+  if (!cvalue) {
+    wpi::ThrowIllegalArgumentException(env,
+                                       "value must be a native ByteBuffer");
+    return;
+  }
+  reinterpret_cast<DataLog*>(impl)->AppendRaw(
+      entry, cvalue.uarray().subspan(start, length), timestamp);
 }
 
 /*
@@ -177,9 +254,10 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_appendRaw
  */
 JNIEXPORT void JNICALL
 Java_edu_wpi_first_util_datalog_DataLogJNI_appendBoolean
-  (JNIEnv*, jclass, jlong impl, jint entry, jboolean value, jlong timestamp)
+  (JNIEnv* env, jclass, jlong impl, jint entry, jboolean value, jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->AppendBoolean(entry, value, timestamp);
@@ -192,9 +270,10 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_appendBoolean
  */
 JNIEXPORT void JNICALL
 Java_edu_wpi_first_util_datalog_DataLogJNI_appendInteger
-  (JNIEnv*, jclass, jlong impl, jint entry, jlong value, jlong timestamp)
+  (JNIEnv* env, jclass, jlong impl, jint entry, jlong value, jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->AppendInteger(entry, value, timestamp);
@@ -207,9 +286,10 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_appendInteger
  */
 JNIEXPORT void JNICALL
 Java_edu_wpi_first_util_datalog_DataLogJNI_appendFloat
-  (JNIEnv*, jclass, jlong impl, jint entry, jfloat value, jlong timestamp)
+  (JNIEnv* env, jclass, jlong impl, jint entry, jfloat value, jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->AppendFloat(entry, value, timestamp);
@@ -222,9 +302,10 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_appendFloat
  */
 JNIEXPORT void JNICALL
 Java_edu_wpi_first_util_datalog_DataLogJNI_appendDouble
-  (JNIEnv*, jclass, jlong impl, jint entry, jdouble value, jlong timestamp)
+  (JNIEnv* env, jclass, jlong impl, jint entry, jdouble value, jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->AppendDouble(entry, value, timestamp);
@@ -240,6 +321,7 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_appendString
   (JNIEnv* env, jclass, jlong impl, jint entry, jstring value, jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->AppendString(entry, JStringRef{env, value},
@@ -257,6 +339,11 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_appendBooleanArray
    jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
+    return;
+  }
+  if (!value) {
+    wpi::ThrowNullPointerException(env, "value is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->AppendBooleanArray(
@@ -274,6 +361,11 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_appendIntegerArray
    jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
+    return;
+  }
+  if (!value) {
+    wpi::ThrowNullPointerException(env, "value is null");
     return;
   }
   JLongArrayRef jarr{env, value};
@@ -304,6 +396,11 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_appendFloatArray
    jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
+    return;
+  }
+  if (!value) {
+    wpi::ThrowNullPointerException(env, "value is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->AppendFloatArray(
@@ -321,6 +418,11 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_appendDoubleArray
    jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
+    return;
+  }
+  if (!value) {
+    wpi::ThrowNullPointerException(env, "value is null");
     return;
   }
   reinterpret_cast<DataLog*>(impl)->AppendDoubleArray(
@@ -338,6 +440,11 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_appendStringArray
    jlong timestamp)
 {
   if (impl == 0) {
+    wpi::ThrowNullPointerException(env, "impl is null");
+    return;
+  }
+  if (!value) {
+    wpi::ThrowNullPointerException(env, "value is null");
     return;
   }
   size_t len = env->GetArrayLength(value);
@@ -347,6 +454,8 @@ Java_edu_wpi_first_util_datalog_DataLogJNI_appendStringArray
     JLocal<jstring> elem{
         env, static_cast<jstring>(env->GetObjectArrayElement(value, i))};
     if (!elem) {
+      wpi::ThrowNullPointerException(
+          env, fmt::format("string at element {} is null", i));
       return;
     }
     arr.emplace_back(JStringRef{env, elem}.str());
diff --git a/wpiutil/src/main/native/cpp/jni/WPIUtilJNI.cpp b/wpiutil/src/main/native/cpp/jni/WPIUtilJNI.cpp
index 7accd3075b..b9e98970fc 100644
--- a/wpiutil/src/main/native/cpp/jni/WPIUtilJNI.cpp
+++ b/wpiutil/src/main/native/cpp/jni/WPIUtilJNI.cpp
@@ -2,6 +2,8 @@
 // Open Source Software; you can modify and/or share it under the terms of
 // the WPILib BSD license file in the root directory of this project.
 
+#include "WPIUtilJNI.h"
+
 #include <jni.h>
 
 #include "edu_wpi_first_util_WPIUtilJNI.h"
@@ -15,7 +17,28 @@ using namespace wpi::java;
 static bool mockTimeEnabled = false;
 static uint64_t mockNow = 0;
 
+static JException illegalArgEx;
+static JException indexOobEx;
 static JException interruptedEx;
+static JException nullPointerEx;
+
+static const JExceptionInit exceptions[] = {
+    {"java/lang/IllegalArgumentException", &illegalArgEx},
+    {"java/lang/IndexOutOfBoundsException", &indexOobEx},
+    {"java/lang/InterruptedException", &interruptedEx},
+    {"java/lang/NullPointerException", &nullPointerEx}};
+
+void wpi::ThrowIllegalArgumentException(JNIEnv* env, std::string_view msg) {
+  illegalArgEx.Throw(env, msg);
+}
+
+void wpi::ThrowIndexOobException(JNIEnv* env, std::string_view msg) {
+  indexOobEx.Throw(env, msg);
+}
+
+void wpi::ThrowNullPointerException(JNIEnv* env, std::string_view msg) {
+  nullPointerEx.Throw(env, msg);
+}
 
 extern "C" {
 
@@ -25,9 +48,11 @@ JNIEXPORT jint JNICALL JNI_OnLoad(JavaVM* vm, void* reserved) {
     return JNI_ERR;
   }
 
-  interruptedEx = JException(env, "java/lang/InterruptedException");
-  if (!interruptedEx) {
-    return JNI_ERR;
+  for (auto& c : exceptions) {
+    *c.cls = JException(env, c.name);
+    if (!*c.cls) {
+      return JNI_ERR;
+    }
   }
 
   return JNI_VERSION_1_6;
@@ -39,7 +64,9 @@ JNIEXPORT void JNICALL JNI_OnUnload(JavaVM* vm, void* reserved) {
     return;
   }
 
-  interruptedEx.free(env);
+  for (auto& c : exceptions) {
+    c.cls->free(env);
+  }
 }
 
 /*
diff --git a/wpiutil/src/main/native/cpp/jni/WPIUtilJNI.h b/wpiutil/src/main/native/cpp/jni/WPIUtilJNI.h
new file mode 100644
index 0000000000..541064f2b3
--- /dev/null
+++ b/wpiutil/src/main/native/cpp/jni/WPIUtilJNI.h
@@ -0,0 +1,17 @@
+// Copyright (c) FIRST and other WPILib contributors.
+// Open Source Software; you can modify and/or share it under the terms of
+// the WPILib BSD license file in the root directory of this project.
+
+#pragma once
+
+#include <jni.h>
+
+#include <string_view>
+
+namespace wpi {
+
+void ThrowIllegalArgumentException(JNIEnv* env, std::string_view msg);
+void ThrowIndexOobException(JNIEnv* env, std::string_view msg);
+void ThrowNullPointerException(JNIEnv* env, std::string_view msg);
+
+}  // namespace wpi